Numerous human hormones, neurotransmitters, or therapeutic antibodies are peptides or comprise peptides as a substantial part of their molecular structures. Therapeutically effective amounts of such biologically relevant peptides may be administered to patients in a variety of ways. Oral delivery of pharmacologically active agents is generally the delivery route of choice since it is convenient, self administration is relatively easy and generally painless, resulting in greater patient compliance as compared to other modes of delivery.
Biological, chemical and physical barriers such as varying pH in the gastrointestinal tract, powerful digestive enzymes in the stomach and intestine, and active agent impermeable gastrointestinal membranes, however, often makes the effective delivery of peptide pharmaceuticals problematic. For example, the oral delivery of calcitonins, has proven difficult due, at least in part, to the insufficient stability of calcitonin in the gastrointestinal tract as well as the inability of calcitonin to be readily transported through the intestinal walls into the blood stream.
Consequently, peptide pharmaceuticals used in the prior art frequently have been administered by injection or by nasal administration. Insulin is one example of a peptide pharmaceutical frequently administered by injection. Injection and nasal administration, however, are significantly less convenient than, and involve more patient discomfort than, oral administration. Often this inconvenience or discomfort results in substantial patient noncompliance with a treatment regimen. Thus, there is a need in the art for more effective and reproducible oral administration of peptide pharmaceuticals like insulin, calcitonin and others discussed in more detail herein.